Why do mammalian feotus have so many similar structures to the amniotic egg?

Answer 1

Mammalian fetuses exhibit similarities to the amniotic egg structures due to their shared evolutionary heritage and the necessity for protection and nourishment during development. Both utilize membranes such as the amnion, chorion, and allantois to provide a controlled environment, facilitate gas exchange, and manage waste. These adaptations enhance survival rates by ensuring that developing embryos are safeguarded from external conditions, similar to the functions of the amniotic egg in reptiles and birds. Thus, these structures reflect convergent evolutionary solutions to reproductive challenges in terrestrial environments.